1. Field of the Invention
The present invention relates to a method for producing L-lysine by fermentation, and particularly relates to a method for producing L-lysine with a microorganism constructed by a gene recombination technique.
2. Description of the Prior Art
Hitherto, in order to render a wild strain capable of producing L-lysine from carbohydrates, it has been necessary to induce artificial mutants from the wild strain. There are many known lysine-producing artificial mutants. Most of the known lysine-producing mutants are resistant to lysine-analogues such as S-(2-aminoethyl)-cysteine (AEC), and/or require homoserine for growth, and belong to the genus Brevibacterium or Corynebacterium. These microorganisms produce L-lysine in a yield of from 40 to 50%. Examples of recent publications concerning L-lysine production by fermentation are: Japanese Published Unexamined Patent Application Nos. 9784/1980, 9783/1980, 9559/1980, 9785/1980, 86091/1978, 86090/1978, 86089/1978, 26391/1978, 20490/1978, 9394/1978 and 6486/1978.
It has however, become difficult to increase the yields of L-lysine using the artificial mutation techniques. A need therefore, continues to exist for the development of novel microorganisms capable of producing L-lysine in high yields.